Question 1

Which of the following is the most immediate source of energy for skeletal muscle contraction?

Accepted Answer

Creatine phosphate donating a phosphate to ADP

Question 2

During a 100-meter sprint lasting about 10 seconds, which energy source is primarily used by skeletal muscle fibers?

Accepted Answer

Immediate ATP and creatine phosphate stores

Question 3

Which of the following best describes the glycolytic mechanism for ATP production in muscle fibers?

Accepted Answer

It rapidly produces ATP in the cytoplasm without requiring oxygen.

Question 4

A marathon runner relies primarily on which ATP-generating mechanism during the majority of the race?

Accepted Answer

Oxidative phosphorylation

Question 5

Which of the following equations correctly represents the reaction by which creatine phosphate regenerates ATP in muscle fibers?

Accepted Answer

$$\mathrm{Creatine~phosphate} + \mathrm{ADP} \rightarrow \mathrm{Creatine} + \mathrm{ATP}$$

Question 6

Which ATP source can fuel muscle activity for the longest duration?

Accepted Answer

Oxidative phosphorylation

Question 7

A patient with a mitochondrial disorder is likely to have difficulty with which type of muscle activity?

Accepted Answer

Sustained, endurance activities like long-distance running

Question 8

Which of the following statements about glycolysis in muscle fibers is correct?

Accepted Answer

It can supply ATP for about 30–40 seconds of maximal activity.

Question 9

Which process is most likely to be the primary ATP source during a 2-minute high-intensity exercise?

Accepted Answer

Glycolytic pathway

Question 10

Which of the following best explains why oxidative phosphorylation is slower than glycolysis in producing ATP?

Accepted Answer

It depends on the availability of oxygen and involves multiple mitochondrial steps.

Question 11

A weightlifter performing a single maximal lift is primarily using which energy system?

Accepted Answer

Immediate ATP and creatine phosphate stores

Question 12

Which of the following is a correct sequence of ATP source utilization during a 5-minute intense exercise?

Accepted Answer

Immediate ATP → Glycolysis → Oxidative phosphorylation

Question 13

Which of the following is a byproduct of glycolytic ATP production in muscle fibers under anaerobic conditions?

Accepted Answer

Lactic acid

Question 14

Why does muscle fatigue occur more rapidly when relying on glycolytic ATP production compared to oxidative phosphorylation?

Accepted Answer

Glycolysis leads to accumulation of lactic acid, lowering pH.

Question 15

Which of the following best describes the duration that immediate ATP and creatine phosphate stores can fuel maximal muscle activity?

Accepted Answer

Less than 10 seconds

Energy Sources of Skeletal Muscle

Study Guide - Practice Questions